ITV is to launch its long-awaited TV micropayment system in January, as the broadcaster forecast an end to its summer advertising slump in September with television ad revenues expected to be "broadly flat".

ITV, which announced its first payment to shareholders since 2008 with an interim dividend of 0.4p in results for the six months to 30 June, said it intends to launch a range of pay systems for its online television service ITV Player.

The broadcaster added that total revenues were up 4% year on year to £1.03bn in the six months to the end of June. Within this the broadcasting and online division grew revenues by 3% to £887m.

Online revenues increased by 33% year on year as the ITV Player recorded a 19% increase in average monthly unique users and "long-form video views" – essentially whole TV shows watched via PC or handheld devices such as phones and tablets – rose 64% to 180m.

"Our pay mechanism will launch at the turn of the year; we have picked our partners," said the ITV chief executive, Adam Crozier. "We are working on the consumer proposition, what people are prepared to pay for and what will work and won't work."

Crozier said ITV would probably run a number of different [payment] models in the first few months after the launch.

The broadcaster has been experimenting with different online viewing models with "register-to-view trials" for Champions League matches, Indian Premier League games, The Only Way is Essex and webisodes of Coronation Street.

"We originally said there was a possibility of doing it then [in the fourth quarter]," he said. "From a technical point of view we could do it but we want the consumer proposition right. We want a softer launch."

ITV, which has experienced a tough early summer, reporting the first fall in TV ad revenue in 18 months in May, said TV ad revenues will be down 2% in July and 4% in August.

Looking ahead to September, a key month for the broadcaster, ITV is tentatively forecasting TV ad revenue to be "broadly flat" year on year. The broadcaster said that overall TV ad revenue across the third quarter will be "slightly down" year on year, but ahead of the market.

Commenting on the level of the dividend, Crozier said that the aim was for a "dividend that was sustainable" and that ITV has adopted a "progressive policy" for future payouts.

ITV will be particularly pleased with what analysts at UBS described as a "stronger than expected" performance at ITV Studios, the broadcaster's in-house production arm, which increased its total revenues by 4% year on year to £264m.

The performance was primarily driven by ITV Studios' international production operation, which helped boost the division's "external revenues" – commissions for broadcasters other than ITV – by 11% to £140m.

"While there's still a long way to go, we're starting to see potential in the level of new work coming through ITV Studios with 68 new commissions so far this year, of which 29 are international," said Crozier.

Crozier pointed to the success of Prime Suspect, which is being remade for the US in a co-production for NBC, and Titanic, which has been penned by Downton Abbey creator Julian Fellowes and already sold to 15 broadcasters.

Earnings before interest, tax and amortisation at the division fell by £5m, to £38m, but Crozier said this was primarily due to a strategy of investing in new talent and more pilots.

Asked about looking at making acquisitions to boost the production division – ITV has just £52m in debt and has access to almost £1bn in cash – Crozier said that the real issue was looking to organically fix ITV Studios.

Crozier also said that ITV is not working on any plans to potentially buy back the TV rights to Formula One motor racing, which the BBC is widely expected to drop when the current deal expires.

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